1. Field of the Invention
The present invention relates to two-way mobile communication devices and, more particularly, to a spelling error detection and correction system for two-way mobile communication devices.
2. Description of the Related Art
There are already several hundred million subscribers of wireless communication services throughout the world. With this proliferation of wireless communications, it is becoming more and more likely that parties will interact with one another in instances where the only means of communication for one or both parties is through wireless communications. The communications between the parties can be social or business related. Wireless communication is achieved when at least one party is making use of a two-way mobile communication device and a wireless network. Two-way mobile communication devices can, for example, include personal digital assistants (PDAs), two-way pagers, mobile (including cellular) phones and palm-sized computing devices.
These two-way mobile communication devices are finding increasing use in applications and functions requiring the input of text strings of significant length. Examples of situations where text strings are input include, but are not limited to, word processing, email, network browsing and narrowband messaging (e.g. Short Message Service (SMS)). Such two-way mobile communication devices typically utilize telephone-type keypads (e.g., keys 0-9, xe2x80x9c*xe2x80x9d, xe2x80x9c#xe2x80x9d etc.), where the characters are mapped onto each key in a many to one fashion, and have limited processing and memory capabilities relative to the personal computing devices performing similar functions. Additionally, as the size and cost of these two-way mobile communication devices decreases, the size of the display screens increases and the space allotted for the keypads continues to be reduced.
This combination of a keypad with many-to-one character mapping residing in a small confined area contributes to the reduced usability of the devices. This reduction in usability contributes to a dramatic increase in misspelled words. For standard computer keyboards one of the principal causes of misspelled words results from operators inadvertently activating a non-intended key in the general vicinity of the intended key. Typically, the operator knows how to spell the word but hits the wrong key. This particular form of input error occurs at a substantially greater rate when two-way mobile communication devices are used for text entry as compared to using a personal computer to enter the same text.
Generally, character input selection utilizing the keypad of a two-way mobile communication device requires the user to vary the number of activations (e.g., press the key multiple times) or vary the time of activation (e.g., hold the key down longer) to select a character of interest. For example, the xe2x80x9c2xe2x80x9d key on a standard telephone keypad is typically assigned the letters xe2x80x9cABCxe2x80x9d and using one methodology, for example, pressing the xe2x80x9c2xe2x80x9d key twice when in a text entry mode of operation causes the letter xe2x80x9cBxe2x80x9d to be selected. Alternatively, pressing the xe2x80x9c2xe2x80x9d key three times causes the letter xe2x80x9cCxe2x80x9d to be selected. Quite frequently the user ends up with an unintended letter because the intended key (e.g., xe2x80x9c2xe2x80x9d) is not activated in the proper manner. As an example, the user intended xe2x80x9cBxe2x80x9d but xe2x80x9cCxe2x80x9d is actually input because xe2x80x9c2xe2x80x9d was pressed three times instead of two times. This type of error is particularly common in two-way mobile communication devices utilizing telephone-type keypad (e.g. keys 0-9, xe2x80x9c*xe2x80x9d, xe2x80x9c#xe2x80x9d etc.) which are of limited size, where the characters are mapped onto each key in a many to one fashion.
A standard spell checking and correcting program for a personal computer word processing program will generally have a dictionary comprised of between 50,000 and 150,000 words for the English language. Because of large size as well as technological and cost considerations it is generally not feasible to have spell checking and correcting programs with similar sized dictionaries in two-way mobile communication devices.
Thus, there exists a need for improved methods and systems for performing spell checking and correcting functions on two-way mobile communication devices.
The present invention relates to improved systems and methods for implementing spell checking and correcting applications on two-way mobile communication devices. The invention includes various aspects which can be utilized individually or in combination.
One aspect of the invention is that after entry of a character string a delimiter key is depressed, thus signaling the end of the character string. The character string is then compared to pre-stored character strings resident in memory (e.g., within a dictionary) of a subject two-way mobile communication device. Character strings for which no matches are found with respect to the pre-stored character strings are identified as being misspelled. The individual elements (e.g., letters) of any identified misspelled character strings will be sequentially exchanged for character elements assigned to the same many to one input element (e.g. input key). Each of the resulting modified character strings generated in this fashion can be compared to the pre-stored character strings resident in the subject two-way mobile communication device. Those character strings which match the pre-stored entries are presented to the user for evaluation and selection or automatic replacement (e.g., replacement without review) if so desired.
Another aspect of the invention is that the sequential exchange of input character string elements will proceed in accordance with the probability that a particular character element will occur in a particular position within the character string. For example if there are no words with xe2x80x9czxe2x80x9d in the second position stored within the resident dictionary then that substitution will not be utilized. By limiting the number of sequences that must be examined, the processing speed is improved which can be particularly important with mobile communication device having limited processing resources.
In one embodiment, these aspects are beneficially applied to provide spell checking and correcting services for email, messaging and/or word processing applications resident on two-way mobile communication devices. The two-way communication devices are typically hand-held devices having limited size display screens. The two-way communication devices can, for example, be mobile telephones, Personal Digital Assistants (PDA) and Palm-Sized Computing Devices.
The invention can be implemented in numerous ways, including as a method, an apparatus or device, a user interface, a computer readable medium, and a system. Several embodiments of the invention are discussed below.
As a method for spell checking and correcting of character strings input to a mobile device through use of keys of the mobile device, one embodiment of the invention includes the operations of: (a) receiving a character input; (b) determining whether the character input is a predetermined delimiter character; (c) adding the character input to a character string when the determining (b) determines that the character input is not the predetermined delimiter character; (d) performing an initial dictionary look-up for the character string when the determining (b) determines that the character input is the delimiter character; (e) performing character substitutions on at least one character in the character string to produce a modified character string when the performing (b) of the initial dictionary look-up does not locate the character string, the character substitutions being limited to other characters mapped to a common key of the keys of the mobile device; and (f) performing a subsequent dictionary look-up for the modified character string following the performing (e) of the character substitutions.
As a method for performing spelling error detection and correction for a two-way mobile communication device having a display screen and a telephone-type keypad, where input characters are mapped onto the keys in a many to one fashion, one embodiment of the invention includes: storing a plurality of acceptable character strings and associated information within an on-board dictionary resident within the two-way mobile communication device; receiving an input character string where an end of the input character string is indicated by a termination character; comparing the received input character string to the acceptable character strings and providing an indication when a character string substantially matching the received input character string is not found within the on-board dictionary; replacing the individual characters of the received input character string for which no substantial matches were found with characters mapped to the same key of the telephone-type keypad to generate a plurality of associated character strings; and comparing the associated character strings to the acceptable character strings to identify those of the associated character strings that substantially match the acceptable character strings within the on-board dictionary.
As a computer readable media including computer program code for spell checking and correcting of character strings input to a mobile device through use of keys of the mobile device, one embodiment of the invention includes:
computer program code for receiving a character input;
computer program code for determining whether the character input is a predetermined delimiter character; computer program code for adding the character input to a character string when the computer program code for determining determines that the character input is not the predetermined delimiter character;
computer program code for performing an initial dictionary look-up for the character string when the computer program code for determining determines that the character input is the delimiter character; computer program code for performing character substitutions on at least one character in the character string to produce a modified character string when the computer program code for performing of the initial dictionary look-up does not locate the character string, the character substitutions being limited to other characters mapped to a common key of the keys of the mobile device; and computer program code for performing a subsequent dictionary look-up for the modified character string following the computer program code for performing of the character substitutions.
As a wireless two-way interactive communication device, one embodiment of the invention includes: a display screen; a telephone-type keypad, where the characters are mapped onto the keys in a many to one fashion; a storage device for storing a plurality of acceptable character strings and associated information within an on-board dictionary resident within the two-way mobile communication device; a memory for storing program code for a processor; a processor coupled to the storage device and the memory. The processor operates to execute the program code stored in the memory to identify input character strings which do not correspond to at least one of the acceptable character strings in the storage device, to generate replacement character strings for the identified input character strings using replacement characters being mapped to the same key as the character in the identified input character string being replaced, and then to identify those of the replacement character strings that correspond to at least one of the acceptable character strings in the storage device.
The advantages of the invention are numerous. Different embodiments or implementations may yield one or more of the following advantages. One advantage of the invention is that users of two-way mobile communication devices are provided with spell checking and correcting services which specifically addresses one of the most frequently encountered input errors. Another advantage of the invention is that the spell checking and correcting services can be provided on two-way mobile communication devices without the overhead associated with larger spelling applications/modules resident on larger personal computer (PC) systems (e.g., spell checking for PC word processing programs. Yet another advantage of the invention is that by limiting the number of combinations (e.g., two letters for input keys xe2x80x9c2xe2x80x9d, xe2x80x9c3xe2x80x9d, xe2x80x9c4xe2x80x9d, xe2x80x9c5xe2x80x9d, xe2x80x9c6xe2x80x9d, and xe2x80x9c8xe2x80x9d and three letters for xe2x80x9c7xe2x80x9d and xe2x80x9c9xe2x80x9d) the time required to process all the possible combinations is dramatically reduced and thus less burdensome on two-way mobile communication devices.
Other aspects and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.